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United States Patent | 5,337,175 |
Ohnsorge ,   et al. | August 9, 1994 |
Optical communications system for the subscriber area with optical amplifiers. The system according to the invention is used to distribute information signals, particularly telephone signals, from a center to a plurality of subscribers and to make possible a bidirectional transmission of telephone and data signals between the center and the subscribers. According to the invention, the network used for this purpose is a multistar fiber-optic network in which fiber-optic amplifiers (10, 11) are present between successive branch points. The information signals to be distributed are transmitted via the fiber-optic network with a first wavelength (.lambda..sub.1) to the subscribers, and the subscriber-specific information signals to be transmitted from the center (1) to the subscribers (T.sub.i) are converted by frequency modulation to a different frequency band (FB.sub.2) than the distribution signals (by frequency modulation) and transmitted to the subscribers at the same wavelength as the distribution signals, and the subscriber-specific signals to be transmitted from the subscribers (T.sub.i) to the center (1) are converted by frequency modulation to another frequency band (FB.sub.3) and are transmitted optically to the center with a second wavelength (.lambda..sub.2). This optical signal is amplified at suitable points (A) and several alternative embodiments for this amplification are indicated.
Inventors: | Ohnsorge; Horst (Freiberg, DE); Weygang; Adolf (Stuttgart, DE); Heidemann; Rolf (Tamm, DE) |
Assignee: | Alcatel N.V. (Amsterdam) |
Appl. No.: | 833935 |
Filed: | February 11, 1992 |
Feb 11, 1991[DE] | 4104084 | |
May 22, 1991[DE] | 4116660 |
Current U.S. Class: | 398/72; 398/1; 398/92; 398/167.5 |
Intern'l Class: | H04J 014/00; H04B 010/00; H04B 010/02; 345 |
Field of Search: | 359/113,114,115,118,119,120,121,123,124,125,152,173,174,175,176,177,178,179,341 379/53,54 358/85,86 |
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